Diffusion plates in gas generators



Nov. 1, 1932. .1. M. RUsBY DIFFUSION PLATES IN GAS GENERATORS 2 Sheets-Sheet l Filed Jan. 2l, 1929 Nov. l, 1932. J. M. RUSBY I DIFFUSION PLATES IN GAS GENERATORS Filed Jan. 21, 1929 2 Sheets-Sheet Y F/G 2.

(/on M Pas? Q ,WMI/Mx Patented Nov. 1, 1932 UNITED STATES PATENT oEFIcE JOHN M. RUSBY, OF PHILADELPHIA, PENNSYLVANIA, ASSIG-NOR TO THE UNITED GAS IMPROVEMENT COMPANY, F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA DIFFUSION PLATES IN GAS GENERATORS Application filed January 21, 1929.

The present invention relates to gas generators. The object of the invention is to provide improved means to effect a better distribution, in the upper portion of the fuel column of a gas generator, of the gases which are passed through the column.

It is particularly adapted to water gas generators using bituminous coal as fuel. In such use of bituminous fuel it is desirable to lo] carbonize the coal in the upper portion of the generator as completely as possible, before its descent to the water gas reaction zone.

This carbonization is generally effected by the passage through the coal of hot gases,

' the air blast gases, and up-run blue gas, in

'some cases the up-run blue water gas alone,

or together with recirculated gases. Superheated steam passed downward through the coal may also be relied on to aid the carbonization. y

A common difficulty in such use of bituminous coal, especially in the larger generators, is its descent in the central portion of the fuel column, to the water gas zone, un;

carbonized. Indeed in some cases a large portion may descend to the grate ungasified.

This lack of carbonization appears to be chiefly due to the difficulty of passing the hot carbonizing gases through the interior por- ,o tions of the upper part of the fuel column which is comprised of bituminous fuel.

There is always a tendency in a gasV generator for the gases to travel along the generator wall due to lower resistance there than in the interior of the fuel. In the case of the use of bituminous fuel, the resistance in the interior is aggravated by the presence of a plastic zone more or less irregular in outline and location, formedv by the melting of the fuel during carbonization.

The net result is vthat the bulk of the carbonizing gases pass upward along the wall and at the periphery of the fuel bed, and carbonization proceeds inward slowly by radiation from the hot wall and a narrow annulus of hot fuel and by the slow conduction of heat to the interior. The uncarbonized coal sags down in the interior of the column. Instead of coke alone being delivered to the water gas zone for efficient gasification, an an- Serial No. 334,996.

nulus of colte with an interior of uncarbonized coal is delivered, with a loss in efficiency and capacity. i

' The narrow annulus of fuel through which Vthe carbonizing gases travel combined with the relatively low conductivity of the fuel, render it diificultto extract the heat from the gases efiiciently and they may come ofi' the top of the fuel bed with a large part of their original sensible heat.

It is the purpose of the present invention to provide diaphragms preferably of metal, extending downward through the upper part of the fuel column, affording a large area of wall surface in the interior of the column along which the heating gases may pass. It is a feature of my invention that, unlike partitions which have been previously proposed to effect a sub-division of the Lipper portion of the fuel bed, these diaphragms do not eX- tend from wall to wall and do not therefore form entirely compartment sections of the fuel bed.

This non-extension from wall to wall permits the passage of gas laterally from one section of the upper part of the fuel bed to another, and tends to equalize the pressure laterally throughout the column. This equalization of pressure tends to produce an equal ficw of gas through the various portions of the fuel bed, and avoids a concentration of the fiow in one section. When partitions running from wall to wall and completely compartmenting the fuel are employed, there is a continual danger of such concentration of iicw in one section with attendant failure of carbonization in the others.

The non-extension of the diaphragms from wall to wall also permits the movement of the diaphragms which in many cases may be very desirable. This motion need notA be great, a slight rocking of the diaphragm, for example, may be suflicient to open up a iissure sufficient for an increased passage of gas over the passage along the diaphragm wall when stationary. Instead of rocking, t-he diaphragm be slightly raised and lowered or it may be raised somewhat and be permitted to sink downward slowly with the fuel. In the latter case, the diaphragm may be tapered in thickness, so that a very slight lifting will open a fissure for the passage of a considerable amount of gas.

The result of the use of these diaphragms is a much more equalized flow of gases through the entire upper portion of the fuel bed and a contacting of the coal in the interior of the bed with the carbonizing gases.

The necessary path of heat travel by conduction through the coal is greatly reduced and the coal in the interior of the column can be carbonized before it reaches the water gas zone.

The hot carbonizing gases are brought in Contact with more fuel and their sensible heat may be largely abstracted and recovered in the top of the fuel bed.

The diaphragms are preferably of heat resisting metal, for reasons of strength and the fact that they need not be thick and take up much space. On the other hand refractory diaphragms may be employed if desired and have the advantage of being able to store more heat from the gases, and to radiate this heat during periods when, as is possible in some processes, no carbonizing gas or a decreased amount of it is passed through the coal. Y

The invention will be further described in connection with the figures which show a form of the invention in a water gas generator chosen for illustration, and in which,

I Figure 1 shows a vertical cross section of a water gas generator provided with diaphragms in the upper portion of the fuel bed. Fig. 2 shows a horizontal cross section along the line 2-2 in Figure 1.

Fig. 3 shows an enlarged cross section of a tapered diaphragm.

Fig. 4 shows a horizontal cross section of another form of diaphragm than indicated in Figs. 1 and 2.

Fig. 5 illustrates another modification in cross section.

Referring to Figures 1 and 2,

One (1) generally indicates the water gas generator chosen for illustration, and having the air blast inlet 2, the steam for uprunning 3, the steam supplies for downrunning 4. Five (5) generally indicates the fuel bed which comprises the water gas reaction zone 6 and the carbonizing zone 7. Eight (8) is an off-take for air blast gases leading off below the carbonizing zone. Nine (9) is an upper gas off-take leading o from above the carbonizing zone for up-run water Vgas and coal gas. Ten (10) is a bottom gas off-take for down-run water gas. Eleven (11) indicates a form of the diaphragms of my invention placed substantially vertical in the upper portion or carbonizing zone of the generator. In the form shown they are flat plates of heat resisting metal of tapering @thickness and suspended by the rods 12 which pass through the stuffing boxes 13 in the generator top.

In the application of my invention illustrated, a slight up and down motion may be given by the gears 14 driven by' any suitable means, and engaging racks on the rods 12.

Figure 3 shows an enlarged cross section of a tapered diaphragm which has been raised, 11 is the diaphragm, 16 indicates the coal being carbonized, 17 indicates the small fissure formed by raising the tapered diaphragm. Arrows indicate an upward flow of hot carbonizing gases. The tapered diaphragm has the advantage of rendering vlittle resistance to the downward movement of the fuel. The diaphragms may be tapered in the other horizontal direction for the same reason. i

Figure 4 shows a horizontal cross section l.,

. l Figure 5 shows a horizontal cross section of a fiuted diaphragm. The iutes are not completely filled by the coal and afford small passages for the passage of the hot gases.

As before stated these diaphragms are prefy erably of heat resisting metal but may be of refractory. The radial arrangement of the diaphragms shown in Figure 2 is optional.

ther arrangements may be desirable depending on method of fuel charging and other conditions.

The water gas generator of Figures 1 and 2 was chosen for illustration. The diaphragms may be employed in what may be termed the present standard water gas generator in which the air blast gas off-take 8 in Figure 1 (intermediate the ends of the fuel bed) is not present, the air blast gases passing through the upper portion of the fuel bed which contains the bituminous fuel undergoingcarbonization and being led off at an upper off-take as 9 in Figure 1.

There are various methods of operating the generator of Figure 1. One, chosen for illustration, will be described.

The coke in the water gas zone 6l is raised to incandescence by an air blast supplied through 2, the blast gases being led olf through 8 to heat storage vessels (not shown). The blast is then shut 0E and steam is admitted to the base of the fuel column through 3. rIhe resulting hot water gas passes upward from the water gas zone 6 into and through the bituminous coal undergoing carbonization in the carbonizing zone 7 travelling along the surfaces of the diaphragms 11 which may be slowly moved up and down by the oscillating gears 14. A portion of the uprun water gas also follows the wall of the generator. The flow is generally indicated les Clif" by the arrows. Instead of taking the air blast gases off at 8, all or part of them may be passed through the carbonizing zone to give a greater volume of hot gas for carbonization.

The above is only one ofmany processes to which the diaphragms of my invention may be applied. rlhey are intended for use in any process in which hot gases are passed through the fuel column of a gas generator, and Will effect an improved distribution of the gases through the column.

I claim:

l. Apparatus for the manufacture of gas, comprising a Water gas generator adapted to contain a. fuel bed comprising a layer of incandescent coke surmounted by a layer of coal, and separate substantially flat plates mounted in the upper end of said generator but spaced from the outer Wall and from the center of the generator and completely surrounded by the fuel in said bed.

2. Apparatus for the manufacture of gas, comprising a Water gas generator adapted to contain a fuel bed comprising a layer of incandescent coke surmounted by a layer of coal, and separate substantially flat plates radially mounted in the upper end of said generator but spaced from the outer Wall and from the center of the generator so as to reciprocate vertically and having tapered cross sections and completely surrounded by the fuel in said bed.

3. Apparatus for the manufacture of gas, comprising a Water gas generator adapted to contain a fuel bed comprising a layer of incandescent coke surmounted by a layer of coal, and plates radially mounted in the upper end of said generator but spaced from the outer Wall and from the center of the generator so as te reciprocate vertically and having tapered cross section and corrugatons thereon to afford passages for the gas through the fuel bed and completely surrounded by the fuel in said bed.

JOHN M. R'USBY. 

